User:Jmead2/sandbox
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Speleothem Addition Overview[edit]
The primary focus of my additions will be around the various uses of speleothems as achrives, and the different ways proxy data is pulled from the samples, such as through drip water discharge and cave temperatures. There are a few other issues with the page, included dead sources, that I will look into cleaning up as well. A few sources that I'll be starting with include a range of specialties, but I'm still sifting though more generalized materials for better scope. [1][2][3][4]
As climate proxies (Draft)[edit]
Speleothems are studied as climate proxies because their location within cave environments and methods of growth allow them to be archives for several different climate records, including drip rates, oxygen and carbon isotopes, and trace cations. These indicators, alone and in conjunction with other climate proxy records, can provide clues to past precipitation, temperature, and vegetation changes over the last ~ 500,000 years [1].
A particular strength of speleothems is their ability to be accurately dated over much of the late Quaternary period using the uranium-thorium dating technique [5]. Stable isotopes of oxygen (δ18O) and carbon (δ13C) are recorded well in speleothems, giving high-resolution data that can show annual variation in records of precipitation and temperature[4].
Samples taken from speleothems can be used like ice cores or tree rings, where new growth layers are used as a proxy record of past precipitation. Variations in precipitation alter the width of new ring formation, where close ring formation shows little rainfall, and wider spacing for heavier rainfall [6].
The geometrical way in which stalagmites grow is also used in paleoclimate applications, which varies based on the height the water is falling from, and the rate of flow. Weaker flows and short travel distances form more narrow stalagmites, while heavier flow and a greater fall distance tends to form more broad ones [1]. Additionally, drip rate counting and trace element analysis on the water drops themselves have been shown to record shorter-term variations in the climate at high resolution, such as drought conditions attributed to the El Niño-Southern Oscillation (ENSO) climate events [2].
A recent technique is the use of CT-scanning on intact specimens to analyze density, where more dense speleothem development indicates higher moisture availability [7].
- ^ a b c Fairchild, Ian J.; Smith, Claire L.; Baker, Andy; Fuller, Lisa; Spötl, Christoph; Mattey, Dave; McDermott, Frank; E.I.M.F. (2006-03-01). "Modification and preservation of environmental signals in speleothems". Earth-Science Reviews. ISOtopes in PALaeoenvironmental reconstruction (ISOPAL). 75 (1–4): 105–153. doi:10.1016/j.earscirev.2005.08.003.
- ^ a b McDonald, Janece; Drysdale, Russell; Hill, David (2004-11-01). "The 2002–2003 El Niño recorded in Australian cave drip waters: Implications for reconstructing rainfall histories using stalagmites". Geophysical Research Letters. 31 (22): L22202. doi:10.1029/2004GL020859. ISSN 1944-8007.
- ^ Williams, P. W.; King, D. N.T.; Zhao, J.-X.; Collerson, K. D. (2004-02-01). "Speleothem master chronologies: combined Holocene 18O and 13C records from the North Island of New Zealand and their palaeoenvironmental interpretation". The Holocene. 14 (2): 194–208. doi:10.1191/0959683604hl676rp. ISSN 0959-6836.
- ^ a b McDermott, Frank (2004-04-01). "Palaeo-climate reconstruction from stable isotope variations in speleothems: a review". Quaternary Science Reviews. Isotopes in Quaternary Paleoenvironmental reconstruction. 23 (7–8): 901–918. doi:10.1016/j.quascirev.2003.06.021.
- ^ Richards, David A.; Dorale, Jeffrey A. (2003-01-01). "Uranium-series Chronology and Environmental Applications of Speleothems". Reviews in Mineralogy and Geochemistry. 52 (1): 407–460. doi:10.2113/0520407. ISSN 1529-6466.
- ^ "Picture Climate: What Can We Learn From Caves? | NOAA Climate.gov". www.climate.gov. Retrieved 2017-04-29.
- ^ Walczak, Izabela W.; Baldini, James U. L.; Baldini, Lisa M.; McDermott, Frank; Marsden, Stuart; Standish, Christopher D.; Richards, David A.; Andreo, Bartolomé; Slater, Jonathan (2015-11-01). "Reconstructing high-resolution climate using CT scanning of unsectioned stalagmites: A case study identifying the mid-Holocene onset of the Mediterranean climate in southern Iberia". Quaternary Science Reviews. Novel approaches to and new insights from speleothem-based climate reconstructions. 127: 117–128. doi:10.1016/j.quascirev.2015.06.013.